Oil burning furnace and control



Oct. 16, 1956 E. DAVIS 2,

OIL BURNING FURNACE AND CONTROL Filed May 1, 195:5 4 Shets-Sheet 1flail.

45 ATTORNE Oct. 16, 1956 E. DAVIS on. BURNING FURNACE AND CONTROL 4Sheets-Sheet 2 Filed May 1. l953 INVENTOR [AL/J fl/iws BY M Oct. 16,1956 E. DAVIS 2,766,818

OII BURNING FURNACE AND CONTROL Filed'May l. 1953 4 Sheets-Sheet 3INVENTOR I 4 24/5 0410s ATT Oct. 16, 1956 E. DAVIS OIL BURNING FURNACEAND CONTROL Filed May 1, 1953 4 Sheets-Sheet 4 INVENTOR ELL/S DA V/SMMgJW ATTORNEYS United States Fatent Gflice 2,766,818 Patented Oct. 16,1956 OIL BURNING FURNACE AND CONTROL Ellis Davis, Bartow, Fla.

Application May 1, 1953, Serial No. 352,410

4 Claims. (Cl. 158-28) This invention relates to oil burning furnacesand the like and the automatic igniting and control thereof. Thisinvention is particularly concerned with an improved construction andmode of operation for an oil burning space heating furnace which has afully automatic oil supply and ignition control and which also isadapted to be controlled thermostatically to maintain temperatureconditions within acceptable limits.

An object of this invention is to provide an oil burner of improvedconstruction and operation which will maintain the temperatures withinacceptable limits even though there are wide variations in the heatingload.

In the drawings:

Figure 1 is a vertical section with certain parts shown in full lines ofone embodiment of the invention;

Figure 2 is an enlarged vertical section of the igniter and fuel supplyassembly;

Figure 3 is a plan view of the fuel control unit of Figure l with thecover removed and shown at the left of Figure 1;

Figure 4 is a vertical section on the line 44 of Figure 3;

Figure 5 is a horizontal section taken on line 55 of Figure 4;

Figure 6 is an end elevation taken from the right hand end of Figure 4;and

Figure 7 is a schematic wiring diagram of the control system.

Referring now to Figure 1 there is shown a space heater 10 of thepot-burner type wherein a layer of oil 12 is burned in the chamber 14 inthe conventional manner with the expended gases being exhausted throughchimney pipe 16. Positioned in the bottom of chamber 14 is an ignitercoil assembly 18 shown more in detail in Figure 2.

Assembly 18 comprises an outer pipe or conduit 20 threaded into aprojecting nipple 22 fixed in the bottom of chamber 14. The other end ofpipe 20 is closed by a plug 24 which has sealed therein in an insulatingmaterial a central conductor 26 such that an electrical connection canbe made to the interior of the pipe while maintaining the closure fluidtight. Connected to the inner end of the conductor 26 is a stranded wiremember 28 which is positioned centrally within the pipe 20 by insulators21 and projects up into the chamber 14. Fixed to the wire members 28adjacent their upper projecting end is a spiral resistance coil 30 whichperforms the actual igniting of the oil. Coil 39 is electricallyconnected to the wire members 28 at point 32 and to the casing or tube20 at point 34, the pipe 20 being normally grounded as shown inFigure 1. A source of voltage is then connected between ground and thewire members 28 through central conductor 26 of plug 24 and wire 36.Also connected into the pipe 20 at 38 is the oil supply pipe 48 which isconnected through control unit 42 to the oil supply tank not shown.

As shown in Figure 4, the control assembly 42 comprises generally, alower frame portion 44 containing therein oil inlet assembly 46 withfloat controls 48 and 50 appropriate connecting linkages to permit theunified oper-- ation of the device.

In operation the oil from the supply tank not shown is fed into pipe 60through the needle valve 62 into the lower chambers 45 formed by frameportion 44 until the float 48 is raised sufliciently to close ofi needlevalve 62. Float 48 is pivoted at 64 and has a lever arm 66 engagingcollar 68 on the shaft of needle valve 62, so as to force it downwardagainst the action of spring 69 into the closed position as the oillevel rises within chamber 45.

If for any reason float 48 does not shut oif the supply when the desiredlevel is attained, emergency float 50 is provided to prevent flooding ofthe oil burner chamber. Float 50 is positioned within a separate chamber70 and is pivotally mounted on one end of lever 72 which is in turnpivoted in the frame portion 96 at 74. Lever 72 has a catch portion 76which in the normal position engages a lever 78 to hold it in its upperposition. Lever 78 is biased toward its lower position by spring 80connected between arm 82 thereof and frame 96. When float 50 is raisedby an overflow of oil into chamber 70, lever 78 is released and broughtinto contact with the upper end of the stem of the needle valve 62 inhammer-like fashion to force the needle valve closed and shut off theinflow of oil.

Lever 78 may also be controlled by lever 84 which is pivoted in theframe portion 96 at 86 and has thereon cam finger portions 88 and 98.Lever plate 78 carries at its right hand end in Figure 4, cars 92 whichfit into slots in the frame portion 96 (see Figure 3). This permitsmovement of lever 78 in both vertical and horizontal planes. Cam fingerof lever 84 is positioned to engage one of the ears 92 so that whenlever 84 is pivoted counterclockwise in Figure 4, cam finger 9i) pivotslever 78 about the other ear 92 to move the end 79 of lever 78 laterallyout of notch 76 to permit it to be driven downwardly by spring 80 toclose the needle valve 62.

To reset the device the lever 84 is pivoted clockwise in Figure 4 tocause cam finger 88 to press on the end of lever 78 between cars 92which forces end 79 to move upwardly over the rounded bottom of latch 76into the notched position shown in Figure 4 thus releasing the needlevalve 62 to open under the control of the float 48.

As may be seen in Figure 6, lever 84 carries therein a lever rod 98which is also pivotally mounted in a bracket 99 on the frame at 100 andengages at each end thereof solenoids 102 and 104. As may be seen inFigure 6,

energization of solenoid 102 will draw lever 84 downward to lift lever78 into the position shown in Figure 4, and permit the inflow of oilthrough the needle valve ,62 under the control of float 48. Converselyenergization of solenoid 104 will move the lever 84 upwardlycounterclockwise in Figure 4, to release lever 78 to close off needlevalve 62 and stop the inflow of oil into the chamber 45.

The igniter control assembly 56 mounted in the cover 54 comprisesgenerally a lever 106 which is pivotally mounted at 108 and carries atone end a lever extension 110 which is positioned to engage two-wayswitch 112 to switch the apparatus from the igniter to the high fireposition. The other end of lever 106 engages spring guide assembly 114which acts as a guiding control to steady the operation of lever 186.Lever 186 is urged counterclockwise in Figure 4 by pivots 116 connectedto diaphragm 118 mounted in the cover portion 54 by rod 119.Counterbalancing this movement is compressed spring 120 which is mountedbetween one end of lever 122 and a point on lever. 106 between pivot 108and extension 110. The other end of lever 122 is pivotally mounted 3 inthe cover portion 54 at 124. Intermediate it end lever 122 is engaged byscrew bearing assembly 126. Assembly 126 comprises threaded hollow shaft123 carrying at its upper end knob 132 and having mounted therein spring1319. As knob132 is turned clockwise in Figure 5,;shaft' 1.28 advancesdownwardly in Figure 3 to pivot-the lever 122 downwardly to compress thespring 121 Diaphragm "118 is connected through tube 13 .(Figure 1) topressure bulb 136 positioned outside the-chamher 14 and contacting thewall thereof. If desired, bulb 136 may be mounted on the side Wall ofchamber 14 ad jacent the bottom thereof. Thus as the burner heats up,the pressure in pressure bulb 1336 increases expanding diaphragm llwhich lowers pivots 116, permitting lever 1 to pivot clockwise aboutpivot 1138 allowing lever extension 1-10 to actuate two-way switch 112to connect and disconnect the 'ignite'r coil and the high fire control,as will be described in detail herein.

Lever 138 is also mounted about'the pivot point 193 andis adapted toengage plunger 140 of oil outlet control assembly 52 in the lower frameportion 44. Plunger 146 is'in the form of a hollow tube and has anaperture 164 in the side wall thereof adjacent the bottom. Wall 168 ofthe. oil outlet assembly 52 has a corresponding aperture 166 positionedto coincide with aperture 164. and permit oil to flow therethrough intooutlet pipe 170. Thus by varying the position of plunger 140 the outflowof oil may be accurately controlled.

Plunger 140 carries thereon a collar 142 which engages a spring 144which at its lower end abuts the frame 4 1 and thus urges plunger 140toward the upper position shown in Figure 4, stop 146 limiting theupward movement of lever 133 and thus plunger 140. Stop 172 isadjustedrto limit the downward movement of lever 133 so that plunger 14%may not be depressed beyond the low fire position. This leaves a smallportion of apertures 164 and 166 communicating so that oil may flow fromchamber 44 through the tube 176 into the firing chamber 14 of the heater1% whenever the level in chamber 45 is high enough. The position oflever 138 is controlled by the thermostatic control assembly 58 througha finger 150 which engages the upper end of a rod 148 which contactslever 138.

Control assembly 58 comprises. a bimetallic strip 152 having mountedthereon a heating element 154 which is connected through the roomthermostat contacts 157 to a source of power 163 (Figure 7) by the wires156.

Referring now to Figure 7, the master switch 158 v transformer 161 orthe wall thermostat and bimetallic strip energizing transformer 163 tothe power supply in accordance with the movement of lever extension 110,as describedabove.

In operation when it is desired to operate the heater i 10 the masterswitch 158 is manually turned to the on position, which, as describedabove, makes contact 164) and makes and breaks the contact 162'to theoil-on soletained in the energized position as the lever; 78 is engagedby notch 76 of lever 72 and held in the inoperative position. Oil thencontinues to fill the chamber until'the needle valve 62 is closed underthe action of floats4-8 or 5 0 all as described above. In-normaloperation oil will flow from chamber 45 through partially open apertures164 and 166 and thence through pipe 40 into chamber 14 where it contactsthe heated igniter coil and is in turn heated and ignited.

As may be seen more clearly in Figure 2 as the oil flows through pipe41) and nipple 22 into the chamber.

14 it will be heated by the lower portion of the igniter coil 30 withinnipple 22.' This heating will cause the oil within nipple 22 to moveupwardly quite rapidly somewhat in fountain fashionso that it will flowor spray-over the upper portion of the igniter coil 31 which willincrease the overall igniting action. This also tends to a cool theupper exposed portion of coil 30 so that it will not be burned out.

the lever 1436 is urged in the counterclockwise direction in a Figure 4a ainst the action of spring 12% so that the lever extension 111 movesthe switch 112 to the position shown in Figure 7. Thus, when the'masterswitch 158 is closed it connects the igniter coil 311 into the circuit.This heats and ignites the oil 12 flowing into the chamber, '14 as a 7result of the energization of the oil-on solenoid 162.

Gradually as the temperature in the heating chambers] increases pressureis built up in the pressure bulb-diaphragm system causing diaphragm 118to expandand lower the pivot point 116. This permits the lever 106 torotate clockwise under the influence of spring 12! until the switch 112is actuated from the position shown in Figure 7 to the reverse positionto disconnect the igniter coil control transformer 161 and connect thehigh fire oil control transformer 163 across the power .circuit.- Thistransfers control to the wall thermostat which then regulates the flowof oil through the apertures 164 and 166 under the control of thethermostat assembly 58;

The apparatus will then continue on low fire operation until heat iscalled for by the wall thermostat. When this occurs, contact 157 closesand heating element'154 heats the bimetallic strip 152 causing it tomove upwardly from the position shown in Figure 4, to allow rod 148 torise. This allows the lever 133 and the plunger to rise under theinfluence of spring 144 to bring more of aperture 164 into registry withaperture 166. More oil will then flow through the superimposed openings164 and 166 down through the pipe 17 iiinto pipe 49 and then into thechamber 14 providing more fuel and thus more heat until the roomtemperature reaches that called for by the wall thermostat. The furnaceraft tends to create, a

reduced pressure in the furnace chamber 14-,so that there is anincreased dificrential in the pressures in chambers 14 and 45. Thiscauses more oil to flow through pipe 49 p for the high fire operation,and the oil level in chamber 14 may exceed thefi-f inch level which isnormally maintained by float 48. During low fire operation the mainflame is above baffle 178 and .below'bafie 136, and during high fireoperation the principal flame is above baffle 189. Whenthedesiredroomtemperature is reached heater 154 is then deenergized by the opening ofwall thermostat contact 157 and this causes the bimetallic strip 152 to7 7 return to the position shown in Figure 4 and to shut down the oilflow to the low fire condition of operation.

,To turn theheater completely off, switch 15,8 isxthrown up tothe dottedline position show-nin Figure 7 thereby momentarily energizing oil-offsolenoid 1194 and rotating rod 93 clockwise from the position shown'tostop the fiowof oil. 7 7

There is thusprovided a completely automatic control, for starting,igniting and regulating the. operation of; a space heater.

While there is givenabovefa specific example of this invention and itsapplication in practical use, it should be understood that this is notintended to be exhaustive or to be limiting of the invention. On thecontrary, these illustrations and the explanations herein are given inorder to acquaint others skilled in the art with this invention and theprinciples thereof and a suitable manner of its application in practicaluse, so that others skilled in the art may be enabled to modify theinvention and to adapt and apply it in numerous forms, each as may bebest suited to the requirement of a particular use.

I claim:

1. A control device for a fuel burner of the character describedcomprising, supply means including a fuel line for supplying liquid fuelto said burner, igniting means for said fuel, and control means forcontrolling the supply of fuel to said burner in accordance withpredetermined heating requirements, said control means including a firstvalve and a second valve connected in series in said fuel line forcontrolling the flow of oil to said burner, first electro-mechanicalmeans connected to said second valve to vary the opening thereof, meansforming a temperature-responsive electrical circuit to control saidfirst electro-mechanical means in accordance with heating requirements,second electro-mechanical means connected to open and close said firstvalve in accordance with a signal, a master switch for energizing saidmeans for igniting the fuel and also for energizing said secondelectromechanical means to open said first valve when said switch isclosed and for energizing said second electro-mechanical means to closesaid first valve when said switch is opened, control means positioned inheat-exchange relation with the zone of said burner and including aswitch for connecting said first electro-mechanical means to saidtemperature-responsive circuit and also for disconnecting said ignitingmeans from said master switch when the zone of said burner has reached apredetermined temperature whereby a rise in the temperature of theburner above said predetermined temperature places control of the amountof oil supplied to the burner under the control of said second valve.

2. The device as described in claim 1 in which said secondelectro-mechanical means includes an oil-on solenoid and an oil-offsolenoid, and a mechanical linkage coupling the movement of saidsolenoids to said first valve, said oil-0n solenoid being momentarilyactuated to open said first valve when said master switch is turned on,said oil-off solenoid being momentarily actuated to close said firstvalve when said master switch is turned ofl.

3. The device as described in claim 1 in combination with a fueloverflow safety mechanism connected to said first valve in parallel withsaid second electro-mechanical means, said overflow mechanism includinga chamber connected to said fuel line and a float actuated lever forlimiting the level of fuel in said chamber by closing said first valve.

4. A fuel burner control device of the character described comprising,supply means including a fuel line for supplying liquid fuel to theburner, igniting means for igniting said fuel, and means for controllingthe supply of fuel to said burner in accordance with predeterminedheating requirements, said means for controlling including a valveconnected in said line for controlling the flow of oil to said burner,first electro-mechanical means to vary the amount of fuel flowing insaid line, a temperatureresponsive electrical circuit adapted to controlsaid first electro-mechanical means in accordance with heatingrequirements, second electro-mechanical means connected to said valve insaid line for opening or closing the valve in accordance with respectivesignals from a master switch, a master switch for energizing saidigniting means and also for energizing said second electro-mechanicalmeans to open said valve when said switch is turned on and forenergizing this electro-mechanical means to close said valve when saidswitch is turned 01f, control means positioned in heat exchange relationto said burner and including a switch for connecting said firstelectro-mechanical means to said temperature responsive circuit and fordisconnecting said means for igniting from said master switch when saidburner has reached a predetermined temperature whereby a rise in thetemperature of the burner above said predetermined temperature causesthe amount of oil supplied to the burner to be controlled in accordancewith signals from said temperature responsive circuit.

References Cited in the file of this patent UNITED STATES PATENTS2,317,063 Johnson Apr. 20, 1943 2,416,766 Miller et al Mar. 4, 19472,503,260 Hall Apr. 11, 1950

